This invention relates to methods and apparatus for hair transplantation, and in particular to the production of hair transplantation donor strips, i.e. elongate strips of skin having hair, that are removed from the scalp for subsequent transplantation to another area of the scalp.
In a typical hair transplantation procedure, grafts of skin containing hair are removed from the scalp and are transplanted to another area of the scalp. To place the removed grafts into these areas, a number of incisions are first made in the scalp. The incisions are then cleaned and the grafts are inserted into the incisions. When placing the grafts into the incisions, the surgeon attempts to arrange the grafts so that the resulting transplant resembles a normal hairline. To accomplish such a task, it is usually desirable to place only a small number of hairs, e.g., two to six (referred to as a minigraft), or even a single hair (referred to as a micrograft) into the incisions. Exemplary methods and apparatus for hair transplantation are described in co-pending U.S. patent application Ser. No. 08/375,312, filed Jan. 18, 1995 (Attorney Docket No. 16798-1-1), now U.S. Pat. No. 5,611,810, the disclosure of which is herein incorporated by reference. An exemplary apparatus for forming incisions to receive minigrafts is described in co-pending U.S. patent application Ser. No. 08/375,314, filed Jan. 18, 1995 (Attorney Docket No. 16798-2-1), now U.S. Pat. No. 5,693,064, the disclosure of which is herein incorporated by reference.
When performing a hair transplantation procedure, it is common to transplant a large number of grafts, usually about 500 to 600, in one operation. To obtain such a large number of grafts, it is desirable to remove the grafts from the scalp in elongate strips (referred to as donor strips). The donor strips are then separated into smaller grafts having about 1 to 6 hairs and used as transplants.
A prior art apparatus for producing donor strips is shown in FIG. 1. The apparatus includes a multiple blade holder 10. The holder 10 includes a knurled cylindrical handle 12 having a distal end 14 for holding a plurality of blades 24 (see FIG. 2). The blades 24 have a planar geometry and have a sharpened edge. The blades 24 are provided with holes which are received over a pair of pins 16, 18 at the distal end 14. The pin 18 is threaded for receiving a nut 20 which is used to secure the blades 24 to the holder 10. From the top view, the nut 20 is received on the right-hand side of the holder 10. Spacers 26 (see FIG. 2) are provided between the blades so that the blades are held spaced-apart from each other. In this way, a plurality of parallel blades can be held at the distal end 14. To load the blades 24 on the holder 10, the holder 10 is held in the left hand and the blades 24 and spacers 26 are placed over the pins 16, 18 with the right hand. The right hand is then used to apply and tighten the nut 20. The handle 12 includes a groove 22 for receiving the thumb of the surgeon when the handle 12 is grasped.
A prior art method for using the holder 10 of FIG. 1 to produce donor strips is illustrated in FIG. 2. The holder 10 includes three blades 24 that are spaced-apart by spacers 26. Initially, a portion of a patient's head 28 is shaved to produce a uniform hair length of about 3 mm from which the strips will be taken. The holder 10 is then grasped by a hand 30 with the thumb 32 resting in the groove 22. In this way, the hand 30 is held over the holder 10. The blades 24 are then pressed in to the patient's scalp, and the holder 10 is translated, usually in a single and continuous stroke, the length of the shaved area. This produces three parallel incisions along the patient's scalp. The skin lying within the incisions is then removed from the patient's scalp to produce two donor strips.
A serious drawback to the method illustrated in FIG. 2 is that the incisions are usually made without taking into consideration the direction of hair growth in the patient's scalp. Hair grows from the scalp in a variety of directions and varies both from patient to patient and from one area on the scalp to another. In the prior art method, the blades 24 are translated through the scalp in one continuous stroke, which severs some of the hair follicles from the hair. The grafts having these hairs cannot be used for transplantation. When making a single long sweep across the patient's scalp, a significant amount of the viable donor strip can be destroyed. In some cases it is possible to destroy up to about 80% of the viable strip. Grasping of the holder 10 in the manner shown in FIG. 2 contributes to the amount of destruction of the viable strip since such a grip requires translation of both the arm and hand and therefore makes it difficult to control the orientation of the blades when making the incisions.
It would therefore be desirable to provide methods and apparatus for producing hair transplantation donor strips with minimal or no loss of hairs in the strip when the strip is cut and removed from the scalp. Such methods and apparatus should be both efficient and easy to use. The methods and apparatus should further be able to compensate for the varied direction of hair growth in the patient's scalp when forming incisions to produce the donor strips.